Harris d



H. o. STONI'E.

RHEOSTAT. APPLICATION FILED FEB. 8. I9I8.

' 4 SHEETS-SHEET l.

Patented June 24, 1919.

H. D. STONE.

RHEOSTAT.

. APPLQCATION FILED FEB. 8; l9l8. 1,307,643.

4 SHEETS-SHEET 2- Patented June 24, 1919.

H, n. STONE.

RHEOSTATL APPLICATION FILED FEB. 8. I918.

Patented June 24, 1919.

' l nvenfor:

saw (16% x 8. W di ttom H.-D. STONE.

RHEOSTAT.

APPLICATION FILED FEB. s. 1918.

4 SHEEYS-SHEET 4.

cymfenlqr 7C M L), d CO-nl.

- x c/fftornczy,

rm ED sTA'rEs PATENT OFFICE.

' mars n. sroNE, or NEw HAVEN, ooNNEc-rrou'r, ASSIGNOB 'ro 'rnE A. c. GILBERT comPA Y, or NEw HAVE CONNECTICUT, a CORPORATION or coNNacrIcUr.

BHEOSTAT.

.Specification of Letters Patent.

Patented June 24, 1919.

Application filed February 8, 1918. Serial No. 216,058.

To all whom it may concern:

, Be it known that I, H'ARRIs D. STONE, a. citizen of the United States, residin in the city and county of New Haven and tate of Connecticut, have invented certain new and usefullmprovements in Rheostats, of which the following is a full, clear, and exact de- 7 scriptiom.

This invention relates to rheostats, and more particularly to a rheostat adapted to "control-the speed of a small electric motor.

. The object ofthis invention is to provide a small, portable rheostat that permits of a comparatively large range of current control, which is durable in use, and which I may be'mzanufaotured 'ata relatively small cost.

A more particular object of my invention is to provide a small, portable rheostat which is adapted to be placed on the floor and operated by a foottreadle in order to provide a convenient means for controlling the speed of an-"electric motor.

To these and other ends, the invention 2 consists of-thenove'l'features and combinations of pants to be hereinafter described and claimed. In the accompanying drawings,

Figure 1 is a side view of my complete rheostat showing the operating treadle mounted thereupon, in its released position; Fig. 2 is a view similar to Fig. 1, but showing the treadle clamped in its operative position;

Fig. .3 is zan'end view of Fig. 2, looking in the direction of the arrows 3-3 shown in Fig. 2, and showing the treadle out upon the sectionalline 3-3;

Fig. 4 is a plan view of my rheostat, with the operating treadle removed;

Fig. 5 is a side view of the rheostat, with the inclosing casing removed;

Fig. 6 is a view similar to Fig. 5, but taken fat right angles thereto; .Fig. 7 is a plan view of the rheostat,.w1th the inclosing casing removed, and the upper plate being removed by a section taken Just below this plate;

Fig. 8' is an enlarged'section taken on the line 8 80f Fig. 4, looking in the direction of the arrows, and showing the flexible contact members in their normal spaced. relation:

Fig. 9 is a view' similar to Fig. 8, but showing several of the contact members depressed to cut out part of the resistance of the rheostat coils;

.Fig. 10 is a view similar to Figs. 8 and 9, but shows all of the contact members depressed to-cut out all of the resistance of the rheostat coils;

Fig. 11 is an enlarged sectional view, taken on the line 11-11 of Fig. 7, looking in the direction of thearrows; and

Fig. 12 is a bottom view of my rheostat. In'the drawings, I have designated my lmproved rheostat in its entirety by the numeral 10 (see particularly Figs. 5 and 6). This rheostat is'provided with a casing 11 having one face opened and havin an outwardly flared rim 12 formed about t is open- A ing. The rheostat. 10 is provided with a base plate 13, which cooperates with the flared rim 12 to close the opened face of the casing 11 when the same is placed over the rheostat. The opposite face of the casing 11 is also provided with an opening, which opening forms a clearance space for parts pro ecting from the upper face of the'rheostat, which parts will be hereinafter described. The opening last referred to is preferably square and is bounded by the edges of the casing designated by the numeral 14. In order to vide convenient means for securing theiparts of the rheostat 10 to the base 13, and or securing the casing 11 in place upon the base 13, I provide four threaded bolts 15,- which are inserted through openings formed in the base plate 13 and extending through the rheostat structure 10 and through open- :ings formed in the upper face of the casing member 18, whichis secured in place upon this casing by forming drill holes in the opposite ends of this member in order that the same may be placed over the projecting ends of the two remaining bolts 15 and clamped of. this bolt 20 being provided with a head which is positioned to be engaged under the brid e-like member 18 by means of the notch 18 ormed in the bridge member 18 The threads upon the bolt 20 and coiiperating nut 21 provide a convenient adjustable means for retaining the treadle 16 in any desired depressed position, as shown in Fig.

2; The base plate 13 is preferably provided upon its lower face with four rubber feet or lugs 22 in order to prevent the surface upon which my rheostat is placed from being scarred or damaged bythe metal parts of which my device is constructed, and also to prevent the rheostat from slipping upon-the face of the surface-upon which it may rest.

' The base plate 13 preferably has an offset portion formed in the same in which a sheet brass, or some other flexible metal, and are seends thereof. ,Upon the topmost flexible; member -26 is provided an insulating strip 30 I. coiled spring 39, which spring is retained in place upon the pin 19 by I The flexible'strips 26 and '30, as clearlyshown in the drawings, extend of insulating material, such as 23, is placed. Upon each of the threaded bolts 15 ismounted a" spool-like member 24 formed of porcelain, or someother non-conducting material.

Each ofthese members 24 has a' drill hole formed centrally therethrough, which loosely receives the bolts 15, and upon the outer s'urface of these spool-like members are formed a plurality of circumferential grooves 25. In

the rheostat which I have illustrated as dismy invention, 1 have shown each closin spoolike member 24 provided with four circumferential thatthe num 1' may be increased or decreased as may be desired, dependin upon the range of current control it is desired to obtain by the rheostat. Between two of the spool-like members 24 just described, I mount the flexible contact members 26. These members 26 arepreferably formed of cured in place one above the other in a vertical row, as shown in F lgs. 8-11, nclusive. These flexible members are'spaced from each other and are retained in their proper posi-" tion by insulating blocks 27, which blocks are rigidly clamped in place by ,the threaded,

bolts 28,which bolts extend through holes formed in the base plate 13 and through the insulating blocks, and are provided with clamping nuts 29 positioned upon the'upper formed of fiber or some other non-conducting material, the o ject of which is to insulate the sliding pin .19 from the uppermost strip 26. the insulating strip 'ooves 25, it being apparent through the insulating clamping blocks- 27 and project in toward the interior-of "the rheostat 10,.the inner ends of these strips be-' 'ing free to be bent toward each other and sufficiently resilient to spring away from each other when released, as will appear from Figs. 8-10, inclusive. -.The. current resisting means which I have provided formy rheostat consists of a bare, relatively fine" helically coiled wire, designated inv'its entirety by the numeral 31, one end of whlch 33 is secured to a metal strip .32 positioned directly under the bottommost flexible member 26, and the other end 34 of'this-hel-ical wire is secured to the flexible contact member which is the second from the topmost of-the' members 24 and rests in the grooves 25 above mentioned, which grooves retainthe coils in I spaced relation. In this manner the 'adjacent coils are prevented from coming in con- "tact with each other and therefore the wire contact members. The intermediate portion of the helically coiled wire 31 is 'wound. spirally about the four spool-like insulating am able to use for my rheostat over the resistance coils of insulated wire now in gen-t eral use in ,rheostats- The intermediate spaced coils of the'wire 31 are connected to the different contact members 26 by means of finger-like portions 35 whichfare formed integrally upon the outer ends of'the con tact members,

directions sora'sto-straddle the wire 31 and hold the same securely in place without mashing the helical coils'of' the same.

In order to provide means for supporting the sliding pin 19 in'its proper posltion, and

for supportingthe current suppl wires (which will be hereinafter describ place, I provide a square sheet metal plate ,36 having drill holes formed adjacent'each' corner thereof, inorderthat this plate may be mounted uponthe projecting ends of the bolts 15 upon the.upper face of the spoollike-members 24. ThlS plate 36 has formed each contact member being provided Witl1,.'tW0 fingers bent in opposite I ed) in.

near the center thereof a drill hole in which i a collar 37 is mounted,-the same preferably being provided ,with a reduced neck which, projects throughvthefhole formed in the,

plate 36 and is riveted thereto. This collar forms a bearin inwhich the pin 19 above mentioned free y slides, ;the lower end of this pin being provided with ahead 38 p which is tpositioned below the collar 37. The

outer en of this pin 19 :is provided with a The coiled spring '39 serves to normally hold the head 38 of the pin 19 out of contactwith the insulating strip 30. In order to provide means for conducting the current to my rheostat from'any source of supply, such as the ordinary lamp socket, and for conducting the current which has been controlled by the rheostat from the same to the .motor, or other devices open ated thereby, I provide four flexible wire conductors, indicated generally bythe nu-' meral 41. These wires pass into the interior of the rheostat through-a hole formed in the plate 36, which hole is preferably provided with the insulatingcollar 42. One of the wires 41 passes through the collar 42 and has its end 43 secured to the metal strip 32 above mentioned. Another one of the current supply wires 41 passes through the collar 42, and has the end thereof 44 secured to the uppermost flexible contact member 26. The two remaining wires 41 are not electrically connected to any structure within the rheo stat, but simply pass into the rheostat casing through the collar 42 and are secured therein by the clamping member 45,which clamping member is bolted in place by the bolt 46. The clamping member 46, which is rigidly secured to the plate 3.6 by means of the bolt 46, forms a convenient means for securing all fourwires in place, so that the v will not be torn from the 'rheostat by a pn l a upon the same. The two wires 41-last-mentioned in'reality form a single wire, as they do not terminate in the rheostat butsimply pass into and out of. the casing thereof, forming an uninterrupted-lead or conductor. The other lead or conductor of the circuit is formed by the first-mentioned wires 41, be-. tween which the rheostatproper is interposed. 4

The operation of my device is as follows:

The current which is supplied to my rheoe, stat by one ofthe wires 41 is conducted to T the uppermost flexible contact member 26,

and, when the circuit is completed within my rheostat, the current wilipass out of my rheostat through the metal strip 32 and the -'fiexible member 41, which is connected to this strip at 43. When the flexible members 26 assume the position shown in Fig. 8 in i which the outer ends of these members are out of contact with each other, no current can pass through the rheostat, for since the helical Wire 31 does not come into contact with the uppermost contact'26, this contact member is entirely insulated from the other flexible contact members until it'is forced downwardly into engagement with the con tactmember immediately below it. Should the uppermost flexible member 26 be forced downwardly by the pin 19 into electrical engagement with the strip immediately below it,the circuit will then be completed, al-

though the amount of current which is permitted to pass through my rheostat will be materiallyv reduced by the resistance of the helical'wi're 31, as the current will have to my inventive idea.

pass through the entire length of this wire 31 before it reaches the metal strip 32. Should it be .desired to cut out part of the resistance offered by the wire 31, this is done by slightly increasing the pressure.

upon the pin 19 so that one or more ofithe flexible members 26 will be brought into electrical engagement with each other in order to cutout or short-circuit the upper most spaced coils of the-wire 31, the members 26, in this instance, assuming the positions shown in Fig. 9. Should it be desired to cut out all of the resistance offered by the wire is secured to this strip.

Should it be desired to retain the pin 19 in a particular position, for instance that showfi in Fig. '9, for some length of time,

thismay be done by the threaded bolt 20,

the headof which may be engaged under the bridge 18, after this bolt has been adjusted relatively to its nut 21 to retain the free end of the treadle 16 in the desired adjusted'position. It will be apparentthat the object in providing the bolt 20and coopera .ing parts is to enable a person using my rheostat toremove hisfootfrom the pedal 16 when it is no longer necessary to vary the current passing through my rheosta't, at short intervals.

From the above description it will be seen that the flexible contact members 26 and the sliding pin 19 which controls the positionof these contacts, forms a very simple and convenient means which is easily operated by a foot treadle for obtaining any de sired adjustment of my rheostat.

I have not attempted to illustrate or de-' scribe the numerous changes which may be made in the details of the constructionwhich may be adopted within the scope of the invention as defined in the claims. 1 Various changes in the details of the dex'ioe may be made without digressing from the scope of The rheo stat herein illustrated is particularly'intended for controlling'the speed. of- .sewing machine motors and for similar, purposes. The rheostatmay be placed on the floor in a position to be conveniently oper ated by the foot of the person using the sew ing machine, or, if'desiredfit may be operated by hand, since the rheostat is provided with means tor-holding the treadle 16 in any desired adjustment. My rheostat istherefore manually operable'by either the foot or the hand of the person using the same.

What I claim 1s:

1. A rheostat, comprising a hollow recep of flexible contact memtacle, a pluralit rom each other and'posibers insulated -tioned oneabovethe other within'said receptacle, resistance means for electrically connecting the adjacent contact members,

' comprising an non-insulated, relatively fine being .connected to the intermediate contact members, and means for forcing said contact members into contact with each other,-. whereby said spaced coils will be succes sively sh'ort-circuited:

[contact members, whereby the resistance 5 2. A rheostat, comprising a hollow-receptacle, a plurality of spaced contact members insulated from each other mounted in said receptacle, resistance means for electrically j connecting the adjacent contact members, comprising a non-insulated, relatively fine wlre woundabout said. receptacle in spaced coils, said spaced coils being electrically consupporting frame consisting of spaced plates" and pins connectin of'said plates, insu ati'ng members mounted Y on said pins and constructed to support said nected to the diiferentcontact members, and means for bridging the spaces between the means maybe cut in or out of the circuit.

3. In a rheostat, a plurality of-flexible contact. members insulated from each other and positioned one above the other, electric mounted resistance conductors for connecting the adjacent contact members, manually depressible-- means for forcing said contact "members successively into contact with .each other, and clamping means for retaining said. depressible means in any desired depressed position.

heostat, comprising a receptacle having insulating members positioned at the corners thereof, a plurality of spaced contact members insulated from each-other in said receptacle, resistance means for electrically connecting the ad. jacent contact members, non-insulated, relatively -fine wire wound about said receptacle in spaced coils, the coils being held in their spaced'relation by said insulatin corner members, said -coils being electric ly connected to the different and a top plate,.a plurality of spaced'flexible contact members insulated from each other mounted one above the other upon one of comprising a p cutting parts of said contact members, and means for bridging said 'plates, electric resistance" conductors mounted between said plates and connected to theadjacent contact members, and means ting said conductors into and-out of an elec "tric circuit, a casing inclosing said rheostat,

a member slid'ably mounted in saidcasin fono-perating said means, a treadle mounte upon said: casing for operating said 'slidable member, andan adjustable means for-clamping the treadle in thedesired operating position.

supporting frame provided with aipair of spaced plates, a. plurality of electric contact members mounted therebetween in spaced relation one abovethe other, electric resistance conductors for connecting the adjacent contact members, means slidably mounted in one" of. said plates for forcing said flexible members into contact with each other, and a 'treadle mounted upon said supporting frame vfor operating said, sliding means; substantially as described.-

8. In a rheostat, the combination witha the marginal portions platesin spaced relation, electrical resistancemeans comprisingnon insulated, relatively fine wire wound around said insulating memhers in spaced relation and inclosing the inion 9. In a"rhe St& the 'combination witha." support ng frame consisting of spaced plates and pins connecting'said plates,- insulatin l posts mounted on saidpins'and constructe to support said plates inspa'ced relation,

electric resistance means comprising non-in- I sulated, relatively fine wire having a plurality of spaced coils encircling a number of said postsand inclosing the interior of the v ounded by saidposts, and contact members mounted within said inclosureIfor resistance means in and frame but of circuit v g 10. Ina rheostat, the" combination with a supporting frame consisting of' spaced plates and pins connectin the marginal portions of said plates, insu ating members mounted- OIL-881d pins constructed to support said plates inspaced relation, electric resistance 1 80 f 7. In-arhe0stat,"thje combination with a" said posts to inclose the interior of the frame means slidably mounted in one of said bounded by said posts, a plurality of flexible spaced plates for operating said contact contact members insulated from each other members.

and positioned one above the other Within In witness whereof, I have hereunto set 10 5 said inclosure for cutting parts of said remy hand on the 28 day of January, 1918.

sistance means in and out of circuit, and HARRIS D. STONE. 

